Under-reaming bit



March 29, 1955 J. K. MENTON ETAL 2,705,129

U NDER-REAMING BIT Filed April 4, 195a W A l lll m United States Patent 2,705,129 UNDER-REAMING BIT Jack K. Menton and Billy W. Cathcart, Long Beach, Calif. Application April 4, 1952, Serial No. 280,482 2 Claims. (Cl. 25576) This invention relates to an under-reaming bit which is used particularly in the drilling of oil wells and the prime object of our invention is to so mount the outwardly extensible cutters that they will be pressed outwardly by the weight of the drill pipe on the bit, and particuarly when the bit is on bottom.

Another object of our invention is to so mount the extensible cutters on a single transverse journal or pin so that the cutters will tend to drop inwardly by gravity when the bit is lifted off bottom.

Another object of our invention is to provide a novel under-reaming bit construction in which the spaced depending arms of the bit on which the cutters cones are mounted may be reinforced with a horizontal web, thus reinforcing these arms and preventing them from bending outwardly, due to the weight of the drill pipe on the bit.

Still another object of our invention is to provide a novel means of providing circulation through the bit so that fluid is eflectively conducted to the cutter cones when these cones are digging at the bottom of the hole.

Other objects, advantages and features of invention may appear from the accompanying drawing, the subjoined detailed description and the appended claims.

In the drawing:

Figure l is a side elevation of our under-reaming bit.

Figure 2 is a fragmentary longitudinal sectional view of our bit taken on line 22 of Figure 3,

Figure 3 is a fragmentary side elevation of our bit taken at right angles to Figure 1.

Figure 4 is a fragmentary sectional view taken on line 44 of Figure 2.

Figure 5 is a bottom plan view of our bit.

Figure 6 is a perspective view of one of the reaming cutters and the arm upon which it is mounted.

Referring more particularly to the drawing, our underreaming bit consists of a body 1 with integral depending arms 2 and 3, and a threaded pin 4 at the upper end whereby the bit is attached to the drill pipe 5 in the usual and well known manner. The arms 2 and 3 are spaced laterally and are connected by an integral web 6 adjacent the bottom of the bit, this web reinforcing the arms 23 to prevent these arms from spreading due to the great weight which is placed on the bit.

A digging cone 7 is arm 2 A pair of links 9 and 10 are mounted one on each side of the longitudinal center line of the bit and between the arms 2 and 3, that is, these links fit in the space between the 9 and 10 are both journaled is mounted in the arms 2-3 and extends 12 and 13 is collapsed position of the links 9 and 10. is shown in Figure 1. In the reaming position of the cutters 12 and 13 they will be substantially on the same horizontal level as the cutter cones 7 and 8. This position is shown in Figure 2 of the drawing.

To provide circulation through the bit and still maintain a web 6 of substantial size, we provide a chamber 14 in the body 1 of the bit and from this chamber four circulation holes 15 extend downwardly, there being two 2 and 3, and these holes terminate This position cent the upper end thereof and said arms having fluid ports extending vertically therethrough, said ports extending from said chamber to the lower end of said arms,

said threaded p in having a vertically extending bore mounted is transmitted to the fluid chamber and through said ports.

2. An under-reaming bit comprising a body, a threaded pin on the upper end of said body, a pair of spaced arms depending from the body, a web extending between said References Cited in the file of this patent UNITED STATES PATENTS 1,369,959 Booker Mar. 1, 1921 1,467,479 Henritzi Sept. 11, 1923 1,659,769 Dodds Feb. 21, 1928 1,821,474 Mercer Sept. 1, 1931 2,545,037 Kammerer Mar. 13, 1951 

